U.S. patent application number 16/126917 was filed with the patent office on 2019-05-09 for mobile videoconferencing robot system with network adaptive driving.
The applicant listed for this patent is INTOUCH TECHNOLOGIES, INC.. Invention is credited to John Cody Herzog, Charles Steve Jordan, Amante Mangaser, Marco Pinter, James Rosenthal, Jonathan Southard, Yulun Wang.
Application Number | 20190134818 16/126917 |
Document ID | / |
Family ID | 42007921 |
Filed Date | 2019-05-09 |
United States Patent
Application |
20190134818 |
Kind Code |
A1 |
Mangaser; Amante ; et
al. |
May 9, 2019 |
MOBILE VIDEOCONFERENCING ROBOT SYSTEM WITH NETWORK ADAPTIVE
DRIVING
Abstract
A remote control station that controls a robot through a
network. The remote control station transmits a robot control
command that includes information to move the robot. The remote
control station monitors at least one system parameter and scales
the robot control command as a function of the system parameter.
For example, the remote control station can monitor network latency
and scale the robot control command to slow down the robot with an
increase in the latency of the network. Such an approach can reduce
the amount of overshoot or overcorrection by a user driving the
robot.
Inventors: |
Mangaser; Amante; (Goleta,
CA) ; Southard; Jonathan; (Santa Barbara, CA)
; Pinter; Marco; (Santa Barbara, CA) ; Herzog;
John Cody; (Santa Barbara, CA) ; Jordan; Charles
Steve; (Santa Barbara, CA) ; Wang; Yulun;
(Goleta, CA) ; Rosenthal; James; (Santa Barbara,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INTOUCH TECHNOLOGIES, INC. |
Goleta |
CA |
US |
|
|
Family ID: |
42007921 |
Appl. No.: |
16/126917 |
Filed: |
September 10, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15250621 |
Aug 29, 2016 |
10071484 |
|
|
16126917 |
|
|
|
|
14054518 |
Oct 15, 2013 |
9429934 |
|
|
15250621 |
|
|
|
|
13670692 |
Nov 7, 2012 |
8588976 |
|
|
14054518 |
|
|
|
|
12561190 |
Sep 16, 2009 |
8340819 |
|
|
13670692 |
|
|
|
|
61098156 |
Sep 18, 2008 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G05B 19/409 20130101;
G16H 40/67 20180101; Y10S 901/01 20130101; G05D 1/0022 20130101;
G16H 40/63 20180101; G06F 19/3418 20130101; B25J 9/1689 20130101;
G05B 2219/40298 20130101; G05D 2201/0206 20130101; H04N 7/185
20130101; G05B 2219/40174 20130101 |
International
Class: |
B25J 9/16 20060101
B25J009/16; H04N 7/18 20060101 H04N007/18; G16H 40/63 20060101
G16H040/63; G05D 1/00 20060101 G05D001/00; G05B 19/409 20060101
G05B019/409 |
Claims
1-7. (canceled)
8. A remote controlled robot system, comprising: a robot that
includes a camera and moves in response to a robot control command;
and, a remote control station that includes a monitor and is
coupled to said robot through a network, said remote control
station transmits said robot control command that includes
information to move said robot, wherein the robot control command
is a movement command generated by the remote control station based
on user input received via a user input device of the remote
control station and wherein the remote controlled robot system
scales said robot control command based on a monitored network
parameter.
9. The system of claim 8, wherein said scaled robot control command
is linearly proportional to said network parameter.
10. The system of claim 8, wherein said network parameter includes
a ping time.
11. The system of claim 8, wherein said network parameter includes
a video rate.
12. The system of claim 10, wherein said network parameter includes
a video rate.
13. The system of claim 8, wherein said scaled robot control
command is filtered with a low pass filter.
14. The system of claim 8, wherein said scaled robot command
reduces a speed of said robot with an increase in a network
latency.
15. The system of claim 8, wherein said robot includes a monitor,
speaker and microphone and said remote control station includes a
camera, speaker and microphone.
16. A method for remotely controlling a robot that has a camera,
the method comprising: displaying, on a monitor of the remote
control station, an image captured by a camera of the robot;
generating, by the remote control station, a robot control command,
wherein the robot control command is a movement command based on
user input received via a user input device of the remote control
station; monitoring at least one network parameter; scaling, by the
remote control robot system, the robot control command based on the
monitored network parameter; and moving the robot in accordance
with the scaled robot control command.
17. The method of claim 16, wherein the scaled robot control
command is linearly proportional to the network parameter.
18. The method of claim 16, wherein the network parameter includes
a ping time.
19. The method of claim 16, wherein the network parameter includes
a video rate.
20. The method of claim 18, wherein the network parameter includes
a video rate.
21. The method of claim 16, further comprising filtering the scaled
robot control command with a low pass filter.
22. The method of claim 16, wherein the scaled robot command
reduces a speed of the robot with an increase in a network latency.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser.
No. 15/250,621, filed Aug. 29, 2016, pending, which is a
continuation of application Ser. No. 14/054,518, filed Oct. 15,
2013, now U.S. Pat. No. 9,429,934, which is a continuation of
application Ser. No. 13/670,692, filed Nov. 7, 2012, now U.S. Pat.
No. 8,588,976, which is a continuation of application Ser. No.
13/561,190, filed Sep. 16, 2009, now U.S. Pat. No. 8,340,819, which
claims priority to Application No. 61/098,156, filed on Sep. 18,
2008, the contents of which are hereby incorporated by
reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The subject matter disclosed generally relates to the field
of mobile two-way teleconferencing.
2. Background Information
[0003] Robots have been used in a variety of applications ranging
from remote control of hazardous material to assisting in the
performance of surgery. For example, U.S. Pat. No. 5,762,458 issued
to Wang et al. discloses a system that allows a surgeon to perform
minimally invasive medical procedures through the use of
robotically controlled instruments. One of the robotic arms in the
Wang system moves an endoscope that has a camera. The camera allows
a surgeon to view a surgical area of a patient.
[0004] There has been marketed a mobile robot introduced by InTouch
Technologies, Inc., the assignee of this application, under the
trademarks COMPANION and RP-7. The InTouch robot is controlled by a
user at a remote station. The remote station may be a personal
computer with a joystick that allows the user to remotely control
the movement of the robot. Both the robot and the remote station
have cameras, monitors, speakers and microphones to allow for
two-way video/audio communication. The robot camera provides video
images to a screen at the remote station so that the user can view
the robot's surroundings and move the robot accordingly.
[0005] The InTouch robot system typically utilizes a broadband
network such as the Internet to establish the communication channel
between the remote station and the robot. For various reasons the
network may create an undesirable latency in the transmission of
video from the robot to the remote station. When driving the robot
the user primarily uses the video provided by the robot camera.
Latency in the network may result in the user receiving delayed
video images and cause the user to generate robot control commands
that overshoot or overcorrect the movement of the robot.
BRIEF SUMMARY OF THE INVENTION
[0006] A remote control station that controls a robot through a
network. The remote control station transmits a robot control
command that includes information to move the robot. The remote
control station monitors at least one system parameter and scales
the robot control command as a function of the system
parameter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is an illustration of a robotic system;
[0008] FIG. 2 is a schematic of an electrical system of a
robot;
[0009] FIG. 3 is a further schematic of the electrical system of
the robot;
[0010] FIG. 4 is a graphical user interface of a remote
station;
[0011] FIG. 5 is an illustration showing a process for scaling a
robot control command;
[0012] FIG. 6 is a graph showing transfer functions for scaling the
robot control command based on a ping time; and,
[0013] FIG. 7 is a graph showing transfer functions for scaling the
robot control command based on a video rate.
DETAILED DESCRIPTION
[0014] Disclosed is a remote control station that controls a robot
through a network. The remote control station transmits a robot
control command that includes information to move the robot. The
remote control station monitors at least one system parameter and
scales the robot control command as a function of the system
parameter. For example, the remote control station can monitor
network latency and scale the robot control command to slow down
the robot with an increase in the latency of the network. Such an
approach can reduce the amount of overshoot or overcorrection by a
user driving the robot.
[0015] Referring to the drawings more particularly by reference
numbers, FIG. 1 shows a robotic system 10 that can be used to
conduct a remote visit. The robotic system 10 includes a robot 12,
a base station 14 and a remote control station 16. The remote
control station 16 may be coupled to the base station 14 through a
network 18. By way of example, the network 18 may be either a
packet switched network such as the Internet, or a circuit switched
network such has a Public Switched Telephone Network (PSTN) or
other broadband system. The base station 14 may be coupled to the
network 18 by a modem 20 or other broadband network interface
device. By way of example, the base station 14 may be a wireless
router. Alternatively, the robot 12 may have a direct connection to
the network thru for example a satellite.
[0016] The remote control station 16 may include a computer 22 that
has a monitor 24, a camera 26, a microphone 28 and a speaker 30.
The computer 22 may also contain an input device 32 such as a
joystick or a mouse. The control station 16 is typically located in
a place that is remote from the robot 12. Although only one remote
control station 16 is shown, the system 10 may include a plurality
of remote stations. In general any number of robots 12 may be
controlled by any number of remote stations 16 or other robots 12.
For example, one remote station 16 may be coupled to a plurality of
robots 12, or one robot 12 may be coupled to a plurality of remote
stations 16, or a plurality of robots 12.
[0017] Each robot 12 includes a movement platform 34 that is
attached to a robot housing 36. Also attached to the robot housing
36 is a pair of cameras 38, a monitor 40, a microphone(s) 42 and a
speaker(s) 44. The microphone 42 and speaker 30 may create a
stereophonic sound. The robot 12 may also have an antenna 46 that
is wirelessly coupled to an antenna 48 of the base station 14. The
system 10 allows a user at the remote control station 16 to move
the robot 12 through operation of the input device 32. The robot
camera 38 is coupled to the remote monitor 24 so that a user at the
remote station 16 can view a patient. Likewise, the robot monitor
40 is coupled to the remote camera 26 so that the patient can view
the user. The microphones 28 and 42, and speakers 30 and 44, allow
for audible communication between the patient and the user.
[0018] The remote station computer 22 may operate Microsoft OS
software and WINDOWS XP or other operating systems such as LINUX.
The remote computer 22 may also operate a video driver, a camera
driver, an audio driver and a joystick driver. The video images may
be transmitted and received with compression software such as MPEG
CODEC.
[0019] FIGS. 2 and 3 show an embodiment of a robot 12. Each robot
12 may include a high level control system 50 and a low level
control system 52. The high level control system 50 may include a
processor 54 that is connected to a bus 56. The bus 56 is coupled
to the camera 38 by an input/output (I/O) ports 58. The monitor 40
is coupled to the bus 56 by a serial output port 60 and a VGA
driver 62. The monitor 40 may include a touchscreen function that
allows the patient to enter input by touching the monitor
screen.
[0020] The speaker 44 is coupled to the bus 56 by a digital to
analog converter 64. The microphone 42 is coupled to the bus 56 by
an analog to digital converter 66. The high level controller 50 may
also contain random access memory (RAM) device 68, a non-volatile
RAM device 70 and a mass storage device 72 that are all coupled to
the bus 56. The mass storage device 72 may contain medical files of
the patient that can be accessed by the user at the remote control
station 16. For example, the mass storage device 72 may contain a
picture of the patient. The user, particularly a health care
provider, can recall the old picture and make a side by side
comparison on the monitor 24 with a present video image of the
patient provided by the camera 38. The robot antennae 45 may be
coupled to a wireless transceiver 74. By way of example, the
transceiver 74 may transmit and receive information in accordance
with IEEE 802.11b.
[0021] The controller 54 may operate with a LINUX OS operating
system. The controller 54 may also operate MS WINDOWS along with
video, camera and audio drivers for communication with the remote
control station 16. Video information may be transceived using MPEG
CODEC compression techniques. The software may allow the user to
send e-mail to the patient and vice versa, or allow the patient to
access the Internet. In general the high level controller 50
operates to control communication between the robot 12 and the
remote control station 16.
[0022] The remote control station 16 may include a computer that is
similar to the high level controller 50. The computer would have a
processor, memory, I/O, software, firmware, etc. for generating,
transmitting, receiving and processing information.
[0023] The high level controller 50 may be linked to the low level
controller 52 by serial ports 76 and 78. The low level controller
52 includes a processor 80 that is coupled to a RAM device 82 and
non-volatile RAM device 84 by a bus 86. Each robot 12 contains a
plurality of motors 88 and motor encoders 90. The motors 88 can
actuate the movement platform and move other parts of the robot
such as the monitor and camera. The encoders 90 provide feedback
information regarding the output of the motors 88. The motors 88
can be coupled to the bus 86 by a digital to analog converter 92
and a driver amplifier 94. The encoders 90 can be coupled to the
bus 86 by a decoder 96. Each robot 12 also has a number of
proximity sensors 98 (see also FIG. 1). The position sensors 98 can
be coupled to the bus 86 by a signal conditioning circuit 100 and
an analog to digital converter 102.
[0024] The low level controller 52 runs software routines that
mechanically actuate the robot 12. For example, the low level
controller 52 provides instructions to actuate the movement
platform to move the robot 12. The low level controller 52 may
receive movement instructions from the high level controller 50.
The movement instructions may be received as movement commands from
the remote control station or another robot. Although two
controllers are shown, it is to be understood that each robot 12
may have one controller, or more than two controllers, controlling
the high and low level functions.
[0025] The various electrical devices of each robot 12 may be
powered by a battery(ies) 104. The battery 104 may be recharged by
a battery recharger station 106 (see also FIG. 1). The low level
controller 52 may include a battery control circuit 108 that senses
the power level of the battery 104. The low level controller 52 can
sense when the power falls below a threshold and then send a
message to the high level controller 50.
[0026] The system may be the same or similar to a robotic system
provided by the assignee InTouch-Health, Inc. of Santa Barbara,
Calif. under the name RP-7. The system may also be the same or
similar to the system disclosed in U.S. Pat. No. 6,925,357 issued
Aug. 2, 2005, which is hereby incorporated by reference.
[0027] FIG. 4 shows a display user interface ("DUI") 120 that can
be displayed at the remote station 16. The DUI 120 may include a
robot view field 122 that displays a video image provided by the
camera of the robot. The DUI 120 may also include a station view
field 124 that displays a video image provided by the camera of the
remote station 16. The DUI 120 may be part of an application
program stored and operated by the computer 22 of the remote
station 16.
[0028] In operation, the robot 12 may be placed in a home or a
facility where one or more patients are to be monitored and/or
assisted. The facility may be a hospital or a residential care
facility. By way of example, the robot 12 may be placed in a home
where a health care provider may monitor and/or assist the patient.
Likewise, a friend or family member may communicate with the
patient. The cameras and monitors at both the robot and remote
control stations allow for teleconferencing between the patient and
the person at the remote station(s).
[0029] The robot 12 can be maneuvered through the home or a
facility by manipulating the input device 32 at a remote station
16. The robot 12 may be controlled by a number of different users.
To accommodate for this the robot may have an arbitration system.
The arbitration system may be integrated into the operating system
of the robot 12. For example, the arbitration technique may be
embedded into the operating system of the high-level controller
50.
[0030] By way of example, the users may be divided into classes
that include the robot itself, a local user, a caregiver, a doctor,
a family member, or a service provider. The robot 12 may override
input commands that conflict with robot operation. For example, if
the robot runs into a wall, the system may ignore all additional
commands to continue in the direction of the wall. A local user is
a person who is physically present with the robot. The robot could
have an input device that allows local operation. For example, the
robot may incorporate a voice recognition system that receives and
interprets audible commands.
[0031] A caregiver is someone who remotely monitors the patient. A
doctor is a medical professional who can remotely control the robot
and also access medical files contained in the robot memory. The
family and service users remotely access the robot. The service
user may service the system such as by upgrading software, or
setting operational parameters.
[0032] The robot 12 may operate in one of two different modes; an
exclusive mode, or a sharing mode. In the exclusive mode only one
user has access control of the robot. The exclusive mode may have a
priority assigned to each type of user. By way of example, the
priority may be in order of local, doctor, caregiver, family and
then service user. In the sharing mode two or more users may share
access with the robot. For example, a caregiver may have access to
the robot, the caregiver may then enter the sharing mode to allow a
doctor to also access the robot. Both the caregiver and the doctor
can conduct a simultaneous tele-conference with the patient.
[0033] The arbitration scheme may have one of four mechanisms;
notification, timeouts, queue and call back. The notification
mechanism may inform either a present user or a requesting user
that another user has, or wants, access to the robot. The timeout
mechanism gives certain types of users a prescribed amount of time
to finish access to the robot. The queue mechanism is an orderly
waiting list for access to the robot. The call back mechanism
informs a user that the robot can be accessed. By way of example, a
family user may receive an e-mail message that the robot is free
for usage. Tables I and II, show how the mechanisms resolve access
request from the various users.
TABLE-US-00001 TABLE I Access Medical Command Software/Debug Set
User Control Record Override Access Priority Robot No No Yes (1) No
No Local No No Yes (2) No No Caregiver Yes Yes Yes (3) No No Doctor
No Yes No No No Family No No No No No Service Yes No Yes Yes
Yes
TABLE-US-00002 TABLE II Requesting User Local Caregiver Doctor
Family Service Current User Local Not Allowed Warn current user of
Warn current user of Warn current user of Warn current user of
pending user pending user pending user pending user Notify
requesting Notify requesting user Notify requesting user Notify
requesting user that system is in that system is in use that system
is in use user that system is in use Set timeout = 5 m Set timeout
= 5 m use Set timeout Call back No timeout Call back Caregiver Warn
current user Not Allowed Warn current user of Warn current user of
Warn current user of of pending user. pending user pending user
pending user Notify requesting Notify requesting user Notify
requesting user Notify requesting user that system is that system
is in use that system is in use user that system is in in use. Set
timeout = 5 m Set timeout = 5 m use Release control Queue or
callback No timeout Callback Doctor Warn current user Warn current
user of Warn current user of Notify requesting user Warn current
user of of pending user pending user pending user that system is in
use pending user Notify requesting Notify requesting Notify
requesting user No timeout Notify requesting user that system is
user that system is in that system is in use Queue or callback user
that system is in in use use No timeout use Release control Set
timeout = 5 m Callback No timeout Callback Family Warn current user
Notify requesting Warn current user of Warn current user of Warn
current user of of pending user user that system is in pending user
pending user pending user Notify requesting use Notify requesting
user Notify requesting user Notify requesting user that system is
No timeout that system is in use that system is in use user that
system is in in use Put in queue or Set timeout = 1 m Set timeout =
5 m use Release Control callback Queue or callback No timeout
Callback Service Warn current user Notify requesting Warn current
user of Warn current user of Not Allowed of pending user user that
system is in request pending user Notify requesting use Notify
requesting user Notify requesting user user that system is No
timeout that system is in use that system is in use in use Callback
No timeout No timeout No timeout Callback Queue or callback
[0034] The information transmitted between the station 16 and the
robot 12 may be encrypted. Additionally, the user may have to enter
a password to enter the system 10. A selected robot is then given
an electronic key by the station 16. The robot 12 validates the key
and returns another key to the station 16. The keys are used to
encrypt information transmitted in the session.
[0035] The robot 12 and remote station 16 transmit commands through
the broadband network 18. The commands can be generated by the user
in a variety of ways. For example, commands to move the robot may
be generated by moving the joystick 32 (see FIG. 1). The commands
are preferably assembled into packets in accordance with TCP/IP
protocol. Table III provides a list of control commands that are
generated at the remote station and transmitted to the robot
through the network.
TABLE-US-00003 TABLE III Control Commands Command Example
Description drive drive 10.0 0.0 5.0 The drive command directs the
robot to move at the specified velocity (in cm/sec) in the (x, y)
plane, and turn its facing at the specified rate (degrees/sec).
goodbye goodbye The goodbye command terminates a user session and
relinquishes control of the robot gotoHomePosition gotoHomePosition
1 The gotoHomePosition command moves the head to a fixed "home"
position (pan and tilt), and restores zoom to default value. The
index value can be 0, 1, or 2. The exact pan/tilt values for each
index are specified in robot configuration files. head head vel pan
5.0 tilt The head command controls the head motion. 10.0 It can
send commands in two modes, identified by keyword: either
positional ("pos") or velocity ("vol"). In velocity mode, the pan
and tilt values are desired velocities of the head on the pan and
tilt axes, in degree/sec. A single command can include just the pan
section, or just the tilt section, or both. keepalive keepalive The
keepalive command causes no action, but keeps the communication
(socket) link open so that a session can continue. In scripts, it
can be used to introduce delay time into the action. odometry
odometry 5 The odometry command enables the flow of odometry
messages from the robot. The argument is the number of times
odometry is to be reported each second. A value of 0 turns odometry
off. reboot reboot The reboot command causes the robot computer to
reboot immediately. The ongoing session is immediately broken off.
restoreHeadPosition restoreHeadPosition The restoreHeadPosition
functions like the gotoHomePosition command, but it homes the head
to a position previously saved with gotoHomePosition.
saveHeadPosition saveHeadPosition The saveHeadPosition command
causes the robot to save the current head position (pan and tilt)
in a scratch location in temporary storage so that this position
can be restored. Subsequent calls to "restoreHeadPosition" will
restore this saved position. Each call to saveHeadPosition
overwrites any previously saved position. setCameraFocus
setCameraFocus 100.0 The setCameraFocus command controls focus for
the camera on the robot side. The value sent is passed "raw" to the
video application running on the robot, which interprets it
according to its own specification. setCameraZoom setCameraZoom
100.0 The setCameraZoom command controls zoom for the camera on the
robot side. The value sent is passed "raw" to the video application
running on the robot, which interprets it according to its own
specification. shutdown Shutdown The shutdown command shuts down
the robot and powers down its computer. stop stop The stop command
directs the robot to stop moving immediately. It is assumed this
will be as sudden a stop as the mechanism can safely accommodate.
timing Timing 3245629 500 The timing message is used to estimate
message latency. It holds the UCT value (seconds + milliseconds) of
the time the message was sent, as recorded on the sending machine.
To do a valid test, you must compare results in each direction
(i.e., sending from machine A to machine B, then from machine B to
machine A) in order to account for differences in the clocks
between the two machines. The robot records data internally to
estimate average and maximum latency over the course of a session,
which it prints to log files. userTask userTask "Jane Doe" The
userTask command notifies the robot of "Remote Visit" the current
user and task. It typically is sent once at the start of the
session, although it can be sent during a session if the user
and/or task change. The robot uses this information for
record-keeping.
[0036] Table IV provides a list of reporting commands that are
generated by the robot and transmitted to the remote station
through the network.
TABLE-US-00004 TABLE IV Reporting Commands Command Example
Description abnormalExit abnormalExit This message informs the user
that the robot software has crashed or otherwise exited abnormally.
Te robot software catches top- level exceptions and generates this
message if any such exceptions occur. bodyType bodyType 3 The
bodyType message informs the station which type body (using the
numbering of the mechanical team) the current robot has. This
allows the robot to be drawn correctly in the station user
interface, and allows for any other necessary body-specific
adjustments. driveEnabled driveEnabled true This message is sent at
the start of a session to indicate whether the drive system is
operational. emergencyShutdown emergencyShutdown This message
informs the station that the robot software has detected a possible
"runaway" condition (an failure causing the robot to move out of
control) and is shutting the entire system down to prevent
hazardous motion. odometry odometry 10 20 340 The odometry command
reports the current (x, y) position (cm) and body orientation
(degrees) of the robot, in the original coordinate space of the
robot at the start of the session. sensorGroup group_data Sensors
on the robot are arranged into groups, each group of a single type
(bumps, range sensors, charge meter, etc.) The sensorGroup message
is sent once per group at the start of each session. It contains
the number, type, locations, and any other relevant data for the
sensors in that group. The station assumes nothing about the
equipment carried on the robot; everything it knows about the
sensors comes from the sensorGroup messages. sensorState groupName
state data The sensorState command reports the current state values
for a specified group of sensor. The syntax and interpretation for
the state data is specific to each group. This message is sent once
for each group at each sensor evaluation (normally several times
per second). systemError systemError This message informs the
station user of a driveController failure in one of the robot's
subsystems. The error_type argument indicates which subsystem
failed, including driveController, sensorController, headHome.
systemInfo systemInfo wireless 45 This message allows regular
reporting of information that falls outside the sensor system such
as wireless signal strength. text text "This is some The text
string sends a text string from the text" robot to the station,
where the string is displayed to the user. This message is used
mainly for debugging. version version 1.6 This message identifies
the software version currently running on the robot. It is sent
once at the start of the session to allow the station to do any
necessary backward compatibility adjustments.
[0037] The processor 54 of the robot high level controller 50 may
operate a program that determines whether the robot 12 has received
a robot control command within a time interval. For example, if the
robot 12 does not receive a control command within 2 seconds then
the processor 54 provides instructions to the low level controller
50 to stop the robot 12. Although a software embodiment is
described, it is to be understood that the control command
monitoring feature could be implemented with hardware, or a
combination of hardware and software. The hardware may include a
timer that is reset each time a control command is received and
generates, or terminates, a command or signal, to stop the
robot.
[0038] The remote station computer 22 may monitor the receipt of
video images provided by the robot camera. The computer 22 may
generate and transmit a STOP command to the robot if the remote
station does not receive or transmit an updated video image within
a time interval. The STOP command causes the robot to stop. By way
of example, the computer 22 may generate a STOP command if the
remote control station does not receive a new video image within 2
seconds. Although a software embodiment is described, it is to be
understood that the video image monitoring feature could be
implemented with hardware, or a combination of hardware and
software. The hardware may include a timer that is reset each time
a new video image is received and generates, or terminates, a
command or signal, to generate the robot STOP command.
[0039] The robot may also have internal safety failure features.
For example, the robot may monitor communication between the robot
controller and the robot servo used to operate the platform motors.
The robot monitor may switch a relay to terminate power to the
platform motors if the monitor detects a lack of communication
between the robot controller and the motor servo.
[0040] The remote station may also have a safety feature for the
input device 32. For example, if there is no input from the
joystick for a certain time interval (eg. 10 seconds) the computer
22 may not relay subsequent input unless the user presses a button
for another time interval (eg. 2 seconds), which reactivates the
input device.
[0041] The system may also scale one or more robot control commands
based on a system parameter. By way of example, the remote control
station may scale the velocity component of the "drive" command
before transmission to the robot. FIG. 5 shows a process for
scaling a robot control command. In block 200 the station may
determine a scale transfer function based on a ping time. A ping
time is the amount of time between when a test sample is sent from
the remote station to the robot, to when the station receives the
sample from the robot. In general, the ping time may relate to
either round-trip or one way latency in the system. In block 202
the station may determine a scale transfer function based on a
video rate. The video rate is the rate at which the station
displays frames of video from the robot camera. There are a number
of different factors that influence the video rate including but
not limited to, frame and/or packet delay in the network, slow
camera capture time, increased time to compress and/or decompress
the video, data loss, and video delay interrupt timing.
[0042] The scale can be calculated in block 204. The scale y can be
determined in accordance with the following linear piece wise
functions.
y=Y.sub.1 for x.ltoreq.X.sub.cutIn
y=Y.sub.2 for x>X.sub.cutOff
y=Y.sub.1+s.times.(x-X.sub.cutOff) for
X.sub.cutIn<x.ltoreq.X.sub.cutOff
where y is the scale,
S=(Y.sub.1-Y.sub.2)/(X.sub.cutIn-X.sub.cutOff)
[0043] x is the input variable, such as ping time or video rate;
and,
[0044] the capitalized entities are constant values determined by
the application.
[0045] FIG. 6 is a graph that shows scale transfer functions based
on ping time for a common cut-in value of 150 msec (X.sub.cutIn)
and cut-off values of 500, 750 and 1000 msec (X.sub.cutOff). FIG. 6
is a graph that shows scale transfer functions based on video rates
for a common cut-in value of 0 fps and cut-off values of 15, 20, 25
and 30 fps.
[0046] The scale can be determined utilizing both the ping time and
the video rate. For example, the scale can be computed with the
following equation:
Combined_scale=p.times.Ping_time_scale+(1.0-p).times.Video_rate_scale
[0047] The parameter p may have a default value of 0.5 so that the
ping time and video rate have equal weight.
[0048] Referring again to FIG. 5, the calculated scale is filtered
with a low pass filter in block 206. The low pass filter 206 can be
defined by the following general equation:
f.sub.i=.alpha..times.f.sub.in+(1.0-.alpha.).times.f.sub.i-1
[0049] where f.sub.i is the current output [0050] f.sub.i-1 is the
previous output [0051] f.sub.in is the current input, and [0052]
.alpha. is a constant that depends on the sampling period and the
filter's cut-off frequency.
[0053] The robot control command can be scaled in block 208. By way
of example, the velocity command can be scaled with the calculated
filtered scale value. Scaling the velocity command can control
robot movement in response to changes in network latency. For
example, the system can automatically slow down the robot when
there is an increase in the latency of the network. This can assist
in reducing overshoot or overcorrection by the user while driving
the robot.
[0054] While certain exemplary embodiments have been described and
shown in the accompanying drawings, it is to be understood that
such embodiments are merely illustrative of and not restrictive on
the broad invention, and that this invention not be limited to the
specific constructions and arrangements shown and described, since
various other modifications may occur to those ordinarily skilled
in the art.
* * * * *